17... f8f7  18. d1d2  18... d8f8 Not an ideal plan, to say the least. Something went very wrong with Black's opening play. 19. d5b6 An excellent move, preserving the knight and getting ready to open the position with b2-b4. Black's problem is that he has no counterplay. Imagine how Vachier-Lagrave, with such an aggressive style, was feeling without being able to play an active move. 19... a8d8 